Aim: We aimed to evaluate the effect of a betalain-rich red beet concentrate (BRC) on joint discomfort and joint function.Methods: Individuals with self-reported knee discomfort were randomized and blinded to treatment with either oral BRC (50 mg twice a day) or placebo. Symptoms of discomfort and joint function were assessed using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the McGill Pain Questionnaire (MPQ) before treatment and after 5 and 10 days of treatment. The general level of energy was evaluated using a visual analog scale (VAS) at the same time points.Results: In all, 40 individuals were evaluated in this study, 20 in the BRC group and 20 in the placebo group. The mean participant age was 55 years (range: 45–65). All participants completed the study. Individuals receiving BRC had a 27% better MPQ score after 10 days than did individuals in the placebo group (P=0.003). Furthermore, knee function, as measured by WOMAC score, was 26% better in the BRC group than in the placebo group (P<0.0013). Participants receiving BRC had a significantly better VAS score for energy after 5 (P=0.002) and 10 days (P=0.012) of treatment than did individuals receiving placebo.Conclusion: Short-term use of BRC in individuals with knee discomfort significantly improved knee discomfort and joint function, as measured by WOMAC and MPQ scores, and energy, as measured by a VAS.